1. Field of the invention
The present invention relates generally to radio display pagers, and more specifically to a radio display pager having a time-keeping circuit for displaying time of day.
2. Description of the Related Art
A prior art radio display pager, as shown and described in Japanese Patent Provisional Publication (Tokkaisho) 61-92045, receives a paging signal which contains a time-of-day signal in addition to source and destination user addresses and a message. The time-of-day signal indicates the "minutes" and "hours" of the local standard time. The pager includes a time-keeping logic circuit which is calibrated by the received time-of-day signal to produce and display the minute and hour of the local time on a display unit. To constantly display the time of day even when the pager is turned off or located in a place where paging signals cannot be received, the time-keeping logic circuit is driven by clock pulses generated by a local oscillator. Since the local oscillator is not precisely synchronized to the "seconds" of the standard time, the displayed time of day develops a significant amount of deviation from the standard time if the logic circuit is not calibrated for a long period of time.